Incidents of anthrax laced letters being transported through the United States Postal Service (USPS) facilities to unsuspecting recipients has increased awareness of the potential for terrorists and other criminals to use the mail system as a delivery mechanism for large scale introduction of biologics, chemicals, explosives, and other hazardous materials to create chaos or to harm an intended set of victims. There appears to be no current security devices or procedures that are available to provide a limiting means to deter use of the mail system as a way to deliver harmful materials, especially during the initial phases of mail handling or processing. The same deterrent means could be utilized to prevent the placement of nuisance objects, such as soda and beer cans, bottles, or rocks, from being placed in the collection box.
The current opening size for depositing mail into the typical collection box located on a street corner is about 6 inches by 15 inches. Most mail deposited into such a collection box comprise business size envelopes, which are approximately 4⅛ inches by 9½ inches, or smaller sized envelopes. Therefore, the current opening size is larger than required for most, if not all, mail deposited with the postal system through collection boxes. Use of a smaller sized opening would restrict the size of object which could be deposited into the collection boxes.
U.S. Pat. No. 659,486, issued Oct. 9, 1900, to W. H. Mulloy, discloses a mail box having stationary projecting guides with suitable incline for an article to pass therethrough into the mail box and a pivotal cover that covers the stationary projecting guides when in the closed position and exposes the stationary projecting guides when in the open position.
U.S. Pat. No. 5,368,226, issued Nov. 29, 1994, to L. Franceschino, discloses a planar frame element for framing an interior opening of the mail slot.